Contingencies And Commitments (Contingencies And Commitments) (Details) (USD $) In Millions, unless otherwise specified					12 Months Ended				12 Months Ended			12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Consumers Energy Company [Member]	Dec. 31, 2012 Consumers Energy Company [Member]	Dec. 31, 2013 Bay Harbor [Member]	Oct. 31, 2010 Bay Harbor [Member]	Dec. 31, 2013 CERCLA Liability [Member] Consumers Energy Company [Member]	Dec. 31, 2013 Manufactured Gas Plant [Member] Consumers Energy Company [Member] site	Dec. 31, 2013 Electric Utility [Member] item	Dec. 31, 2013 Electric Utility [Member] NREPA [Member] Consumers Energy Company [Member]	Dec. 31, 2013 Gas Utility [Member] NREPA [Member] Consumers Energy Company [Member]	Dec. 31, 2013 Manufactured Gas Plant [Member] Consumers Energy Company [Member] site		Dec. 31, 2012 Manufactured Gas Plant [Member] Consumers Energy Company [Member]		Dec. 31, 2011 DOE Settlement [Member] Consumers Energy Company [Member]
Regulatory Matters [Line Items]
Environmental remediation permit renewal term					5 years
Demand for payment by USEPA						$ 7
Cumulative environmental charge					229
Accrual for environmental loss contingencies					52		3	117		4	1
Discounted projected costs rate					4.34%			2.57%
Site contingency accrual inflation rate					1.00%			2.50%
Remaining undiscounted obligation amount					71			127
Foreign government tax claim on sale	142
Remediation and other response activity costs, minimum							3			4
Remediation and other response activity costs. maximum							9			6	3
Number of boilers alleged to exceed emission limits									14
Alleged number of facilities in violation									3
Number of projects affected by alleged violations									10
Litigation settlement, gross																120
Number of former MGPs								23				23
Regulatory assets, noncurrent	$ 1,530	$ 2,287	$ 1,530	$ 2,287								$ 148	[1]	$ 152	[1]
Authorized recovery, collection period												10 years

[1] These regulatory assets represent incurred costs for which the MPSC has provided, or Consumers expects, recovery without a return on investment.